Hand cleanliness

ABSTRACT

Among other things, systems to encourage compliance with hand washing procedures can include: an infrared emitter that projects a first infrared beam with a transverse cross-section having a first axis and a second axis that is shorter than the first axis, the transverse cross-section having a maximum length along the first axis, the infrared emitter modulating the first infrared beam to transmit a first identification signal; wherein the infrared emitter projecting the first infrared beam is placed such that the first axis of the transverse cross-section of the first infrared beam is substantially parallel to a boundary.

This application claims the benefit of U.S. provisional patentapplication Ser. 61/240,622, entitled Hand Cleanliness, filed Sep. 8,2009. This application is a continuation-in-part of U.S. patentapplication Ser. No. 11/415,687, entitled Hand Cleanliness, filed May 1,2006, which is a continuation-in-part of U.S. patent application Ser.No. 11/353,746, entitled Hand Cleanliness, filed Feb. 14, 2006, which isa continuation-in-part of U.S. patent application Ser. No. 11/157,094,entitled Hand Cleanliness, filed Jun. 20, 2005, the contents of all ofwhich are incorporated here by reference.

BACKGROUND

This description relates to boundary identification and handcleanliness.

Health care workers, food handlers, and others ought to clean theirhands frequently and thoroughly, but they often don't. Better handcleaning habits can be promoted by governmental regulations, companyrules, social pressure, and technology. Techniques that have beenproposed for improving cleaning habits include the use of specialcleaning agents as well as mechanisms and electronic devices toregulate, monitor, and report on how frequently and how effectivelypeople clean their hands.

SUMMARY

In general, the systems and methods described can be used for monitoringwhen devices (e.g., wearable badges, equipment tags, theft preventiontags) cross monitored boundaries such as doorways in a hospital. Eachboundary can be delineated by pairs of emitters one of which isassociated with a first side of the boundary and the other of which isassociated with an opposite second side of the boundary. For example, apair of emitters can be associated with a specific doorway. One emittercan have a signal indicating that the emitter is located “outside” thedoorway (e.g., in a hallway). The other emitter can have a signalindicating that the emitter is located “inside” the doorway (e.g., in aroom entered from the hallway). The systems and methods described canprovide a high-level of reliability in indicating when devices (e.g.,wearable badges, equipment tags) cross monitored boundary while limitingemissions in areas spaced apart from the boundary (e.g., the patientcare portion of a hospital).

In some embodiments, the systems and methods described can beimplemented using infrared (IR) emitters. In some cases, the devices(e.g., wearable badges, equipment tags) being used to track movement,for example, of people and/or equipment can include onboard emittersused to transmit information from the devices to external receivingequipment. The onboard emitters can be switched from a default inactivestate to an active state to transmit information upon receipt of aspecific signal associated with the external receiving equipment. Thisapproach can limit emissions (e.g., radio frequency emissions) from thedevices except when devices are triggered to download information to theexternal receiving equipment. For example, it can be desirable to limitemissions and the patient care portion of a hospital room.

In an aspect, in systems to encourage compliance with hand washingprocedures, the systems include: an infrared emitter that projects afirst infrared beam with a transverse cross-section having a first axisand a second axis that is shorter than the first axis, the transversecross-section having a maximum length along the first axis, the infraredemitter modulating the first infrared beam to transmit a firstidentification signal; wherein the infrared emitter projecting the firstinfrared beam is placed such that the first axis of the transversecross-section of the first infrared beam is substantially parallel to aboundary. Implementations may include one or more of the followingfeatures.

In some embodiments, systems include an infrared emitter that projects asecond infrared beam with a transverse cross-section having a first axisand a second axis that is shorter than the first axis, the transversecross-section having a maximum length along the first axis, the infraredemitter modulating the second infrared beam to transmit a secondidentification signal; wherein the infrared emitter projecting thesecond infrared beam is placed such that the first axis of thetransverse cross-section of the second infrared beam is substantiallyparallel to the boundary on an opposite side of the boundary from thefirst infrared beam. In some cases, the infrared emitter that projectsthe first infrared beam is a first infrared emitter and the infraredemitter that projects the second infrared beam is a second infraredemitter. The boundary can be defined by a doorway though a wall and thefirst infrared emitter can be attached to the wall on one side of thedoorway and the second infrared emitter can be attached to the wall onan opposite side of the doorway.

In some embodiments, systems include a wearable device comprising: aninfrared receiver; an indicator operable to indicate a cleanliness stateof a user's hands; and a control unit operable to control the indicatorof hand cleanliness based at least on part based input from the infraredreceiver. In some cases, the controller of the wearable device compriseslogic operable, on receiving the infrared receiver, to evaluate whetherwearable device is crossing the boundary.

In some embodiments, the infrared emitter projecting the first infraredbeam has elements to attach it to a wall and the boundary is implied bythe wall.

In some embodiments, a ratio of a length of the first axis of the firstinfrared beam to a length of the second axis of the first infrared beamis at least 3:1.

In some embodiments, the infrared emitter projects the first infraredbeam downwards towards a floor and an average length of the first axisof the first infrared beam is between about 20 and 28 inches. In somecases, an average length of the second axis of the first infrared beamis between about 6 and 10 inches.

In some embodiments, systems include a plurality of emitters and eachemitter is operable to transmit an identity signal that includesinformation identifying the transmitting emitter.

In general, in an aspect, methods include: receiving, on a wearabledevice, a first signal representative of a first location; evaluatingwhether the first wearable device is crossing a boundary associated withthe first signal; controlling a cleanliness state of the wearable devicebased on results of the evaluation. Implementations may include one ormore of the following features.

In some embodiments, evaluating whether the wearable device is enteringor leaving a location associated with the first signal comprisescomparing the first signal with a previously stored signal. In somecases, methods include evaluating whether the wearable device isentering or leaving a location associated with the first signal if thepreviously stored location signal is the same as the first signal. Insome cases, controlling the cleanliness state comprises controlling thewearable device to an un-sanitized state if the first signal isdifferent than a most recently stored signal.

In some embodiments, receiving the signal comprises receiving aninfrared signal.

In general, in an aspect, in systems to encourage compliance with handwashing procedures, the systems include: an emitter that projects afirst beam with a transverse cross-section having a first axis and asecond axis that is shorter than the first axis, the transversecross-section having a maximum length along the first axis, the infraredemitter modulating the first beam to transmit a first identificationsignal; wherein the emitter projecting the first beam is placed suchthat the first axis of the transverse cross-section of the first beam issubstantially parallel to a boundary. Implementations may include one ormore of the following features.

In some embodiments, the emitter is a radiofrequency transmitter. Insome cases, the emitter comprises shielding configured to limit lateraltransmission of a radiofrequency signal emitted by the radiofrequencytransmitter.

In some embodiments, the emitter comprises an infrared emitter.

In some embodiments, the emitter is configured to project the first beamin response to a signal from a motion detector.

In general, in an aspect, in systems to encourage compliance with handwashing procedures, the systems include: a first infrared emitter thatprojects a first infrared beam with a transverse cross-section having afirst axis and a second axis that is shorter than the first axis, thetransverse cross-section having a maximum length along the first axis,the first infrared emitter modulating the first infrared beam totransmit a first identification signal; a second infrared emitter thatprojects a second infrared beam with a transverse cross-section having afirst axis and a second axis that is shorter than the first axis, thetransverse cross-section having a maximum length along the first axis,the second infrared emitter modulating the second infrared beam totransmit a second identification signal; wherein the first infraredemitter is placed such that the first axis of the transversecross-section of the first infrared beam is substantially parallel to aboundary; and wherein the second infrared emitter projecting the secondinfrared beam is placed such that the first axis of the transversecross-section of the second infrared beam is substantially parallel tothe boundary. Implementations may include one or more of the followingfeatures.

In some embodiments, the systems include a wearable device including: aninfrared receiver; an indicator operable to indicate a cleanliness stateof a user's hands; and a control unit operable to control the indicatorof hand cleanliness based at least on part based input from the infraredreceiver.

In some embodiments, the first and second infrared emitters haveelements to attach the first and second infrared emitters to a wall andthe boundary is implied by the wall.

In some embodiments, the systems include a plurality of emitters andeach emitter is operable to transmit an identity signal that includesinformation identifying the transmitting emitter.

In some embodiments, the first infrared beam carries informationindicative of which one of two sides of the boundary the first emitteris on.

In general, in an aspect, methods in which information is communicatedwirelessly about a location of a boundary in a space that is traversedby people whose hands need to be clean, the wireless communication beingcommunicated in such a way that a device worn by the person candetermine in which direction the person has traversed the boundary.

In general, in an aspect, methods in which a device worn by a person candetermine from received wireless communications the direction in whichthe person has traversed a boundary of a space in which the person iswalking or traversing.

Implementations may include one or more of the following features.

In some embodiments, the methods include receiving, on the device wornby the person, a first signal representative of a location of anemitter; evaluating whether the device worn by the person is crossing aboundary associated with the first signal; and controlling a cleanlinessstate of the wearable device based on results of the evaluation. In somecases, evaluating whether the device worn by the person is entering orleaving a location associated with the first signal comprises comparingthe first signal with a previously stored signal. Determining the deviceworn by the person is entering or leaving a location associated with thefirst signal if the previously stored location signal is not the same asthe first signal. In some cases, controlling the cleanliness statecomprises controlling the wearable device to an un-sanitized state ifthe first signal is different than a most recently stored signal.

In some embodiments, receiving the signal comprises receiving aninfrared signal.

In general, in an aspect, apparatuses include: a first wearable deviceincluding: a controller operable, on receiving a signal from a sentinel,to evaluate whether wearable device is crossing a threshold monitored bythe sentinel; an indicator coupled to the controller, the indicatoroperable to indicate a cleanliness state of a user's hands; and awireless communication element coupled to the controller, the wirelesscommunication element operable to receive the wireless signaltransmitted by the emitter; wherein the controller is configured to setthe indicator to a not-disinfected state in response to the wirelesssignal transmitted by the emitter. Implementations may include one ormore of the following features.

In some embodiments, the controller of the first wearable devicecomprises logic operable, on receiving the signal from the sentinelunit, to compare relative signal strengths of signals received from thesentinel unit at different times.

In some embodiments, the controller of the first wearable devicecomprises logic operable, on receiving the signal from the sentinelunit, to compare the identity signal with a stored identity signal.

In some embodiments, the wearable device comprises a motion sensingdevice coupled to the controller, the motion sensing device operable tosend information to the controller about motion of the wearable device;and the controller is configured to shut down the controller, thesensor, and the motion sensing device when the information from themotion sensing device has not indicated motion for a set period of time.

In some embodiments, the systems and methods described can provide ahigh-level of reliability in indicating when devices (e.g., wearablebadges, equipment tags) cross monitored boundary while limitingemissions in areas spaced apart from the boundary (e.g., the patientcare portion of a hospital room). In some cases, selective activation ofonboard emitters (e.g., upon receipt of a specific signal associatedwith external receiving equipment) can further limit emissions (e.g.,radio frequency emissions) from the devices except when devices aretriggered to download information to the external receiving equipment atlocations spaced apart from, for example, the patient care portion of ahospital room.

Other advantages and features will become apparent from the followingdescription and from the claims.

DESCRIPTION

FIG. 1 is a perspective view of a badge.

FIGS. 2, 3, and 4 are schematic plan views of three layers of the badge.

FIG. 5 is a sectional side view of a chamber at 5-5 in FIG. 4.

FIG. 6 is a three-dimensional view of a space.

FIG. 7 shows a monitor.

FIG. 8 shows a badge in a badge holder.

FIG. 9 is a schematic view of a campus of buildings.

FIGS. 10 through 13 are outside front, inside front, outside back, andinside back views of a badge.

FIG. 14 is a schematic diagram of a badge.

FIGS. 15A and 15B are schematic views of a cleanliness monitoringsystem.

FIGS. 16A and 16B show a monitor.

FIGS. 17A-17C show a badge.

FIG. 18 is a schematic diagram of a badge.

FIG. 19 is a schematic of badge logic.

FIG. 20 shows base station application architecture.

FIG. 21 illustrates a graphical user interface.

FIGS. 22A-22E are schematic views of a cleanliness monitoring system.

FIG. 23 is a schematic view of a monitor.

FIG. 24 is a schematic view of a badge.

FIGS. 25A-25K are wiring schematics for embodiments of a badge, amonitor, and a base station.

FIG. 26 is a schematic of badge logic.

FIGS. 27A-27D illustrate operation of a cleanliness monitoring system.

FIGS. 28A-28B are schematic views of the monitors of a cleanlinessmonitoring system.

FIGS. 29A-29C are schematic views of the monitors of a cleanlinessmonitoring system.

FIG. 30 is a schematic of base station logic.

FIGS. 31A-31J are wiring schematics for embodiments of a badge, amonitor, and a base station.

The system described here can be used for monitoring, encouraging, andmanaging the hand cleanliness of people who work or are otherwisepresent in places where hand cleanliness is important, for example, toreduce the spread of disease or to reduce contamination of products thatare being manufactured or for other purposes. Important purposes of thesystem include encouraging or even enforcing hand cleanliness, reportingcompliance with institutional or governmental requirements for handcleanliness, and permitting the central and institutional control andmanagement of hand cleanliness enforcement and reporting.

As shown in FIG. 1, in some examples, an identification badge 10 worn bya doctor has red and green lights 12, 14, that indicate that her handsare likely to be respectively in a clean (e.g., disinfected, greenlight) condition or in a not clean (e.g., not disinfected, red light)condition. The two lights are controlled by a control circuit (not shownin FIG. 1) based on (a) information derived from an alcohol (e.g.,ethanol) sensor 16 in the badge, (b) signals from a timer (also notshown in FIG. 1) that tracks the passage of time after the circuit hasdetermined that the hands are likely to be in a disinfected condition,and (c) the state of the logic implemented by the control circuit (alsonot shown). An LCD display 23 provides displayed information that caninclude the status of the badge, the control circuit, or the sensor; thetime; the status of the cleanliness of the doctor's hands; and otherinformation.

In addition to providing the disinfection determining function, thebadge 10 can be of a shape and form and can display informationsufficient to serve a conventional function of complying with governmentand institution regulations that require health care workers to carryvisible identification. For example, the badge includes a photograph 17of the doctor, and other information including the doctor's name 19 andidentification number 21. A typical badge could be approximatelycredit-card size.

Because health care workers are required to carry such badges for otherreasons, providing the disinfection determining function within the samebadge make it more likely that the worker will use that function than ifthe function were provided in a separate device that the worker wasexpected to carry separately. In addition, because the badge worn by aworker must be visible to others in the health care environment, thefeature of the badge that indicates whether the user's hands are cleanor unclean will naturally be visible to others. Thus, the worker, merelyby having to wear the badge, will be subjected to social pressure ofpeers, patients, and managers with respect to the cleanliness of theworker's hands. This makes the use of the disinfection determiningfeature of the badge and the improvement of cleanliness habitsself-enforcing. The institution by whom the worker is employed need onlyprovide badges that include those features without directly managing ormonitoring their use.

A pair of electrodes 24, 26 on either side of the sensor is used todetermine when a finger 28 or other part of the hand or other skin hasbeen placed against or near the sensor. When skin of a finger or otherpart of the hand touches both electrodes, the resistance between themwill decline. By measuring that resistance the control circuit candetect the presence of a finger.

The badge is used by the doctor in conjunction with disinfecting herhands using cleaners of the kind that include ethanol (for example, theliquid known by the name Purell available from GOJO Industries, Akron,Ohio, and which contains 62% ethyl alcohol). Such cleaners areconsidered to be more effective than soaps and detergents in killingbacteria and viruses and are widely used in health care and otherenvironments. When the ethanol-based cleaner is rubbed on the skin ofthe hands, the ethanol kills the bacteria and viruses. The effect willlast for several hours but eventually wears off. Ethanol is volatile andeventually evaporates from the skin, leaving the possibility (whichincreases over time) that live bacteria and viruses will againcontaminate the skin from the air and from objects that are touched, forexample.

The concentration of ethanol on the skin and the decay of thatconcentration from evaporation tend to determine the onset of subsequentcontamination. In turn, the concentration of ethanol on the skin can beinferred by the concentration of ethanol vapor near the skin. By placingthe skin near an ethanol detector for a short period of time, it ispossible to determine the vapor concentration of ethanol and thus toinfer the ethanol concentration on the skin and the disinfected state ofthe skin. When the current inferred concentration is above a threshold,it is possible to make an assumption about how long the hands willremain disinfected.

The badge can be used in the following way to improve the hand cleaninghabits of the user.

In some simple examples, the badge can be configured to determine anddisplay two different states: disinfected and not disinfected.

Except when the badge has recently enough (say within two or threehours) entered the disinfected state due to a measurement cycle in whichan adequate concentration of ethanol vapor had been sensed, the badgewill assume a default state of the user's skin of not disinfected. Thus,when the badge is first powered on, or reset, or the permitted timesince a prior successful measurement has elapsed, the state becomes notdisinfected. When the state is not disinfected the red light is lit andthe word re-test is displayed on the LCD.

In some implementations, the badge can be made to switch from the notdisinfected state to the disinfected state only by a successful ethanolmeasurement cycle. A successful cycle is one in which a finger or otherpart of the body is held in position over the sensor (touching both ofthe electrodes) for a period that is at least as long as a requiredmeasurement cycle (e.g., 30 seconds or 45 seconds or 60 secondsdepending on the design of the circuit), and the concentration ofethanol vapor that passes from the skin into a measurement chamber ofthe sensor is high enough to permit an inference that the skin isdisinfected.

Thus, when the doctor wipes her hands with the cleaner to disinfectthem, she can then press one of her clean fingers against the sensor 16and the two electrodes 24, 26, for, say, 60 seconds.

Touching of both of the electrodes simultaneously by the finger isdetected by the control circuit which then begins the measurement cycle.The control circuit could start the red and green lamps to flashalternately and to continue to do so as an indication to the user thatthe electrodes are both being touched and that the measurement cycle isproceeding. At the end of the sensing cycle, the control circuitdetermines a level of concentration of ethanol and uses the level todetermine whether the finger, and by inference, the hand of the doctoris disinfected. Each time a measurement cycle has been fully completed,the red and green lights may both be flashed briefly to signal that thecycle has ended and the finger may be removed.

The control circuit continually monitors the electrodes to determinewhen a finger or other skin is touching both of the electrodes. Whenthat event is detected, a measurement cycle count down timer (which isinitialized for the number of seconds needed to complete a measurement)is started. At the beginning of a cycle, a voltage is applied to theheater to begin to heat the sensor element. Initially the heater voltagemay be set to a higher than normal value in order to shorten the initialaction period described below. Then the heater voltage is reduced. Atthe end of the measurement cycle, a measurement voltage is appliedacross the series connection of the measurement cell and the seriesresistor, and the voltage across the series resistor is detected andcompared to a threshold to determine whether the state should be set todisinfected or not disinfected.

When the control circuit determines that the hand is disinfected, thecontrol circuit switches to the disinfected state, lights the green lamp(and turns off the red lamp), and displays the word clean on the LCD. Inaddition, upon the initiation of the disinfected state, the controlcircuit starts a re-test count down timer that is initially set to theperiod during which the skin is expected to remain disinfected (forexample two hours).

If the control circuit is in the disinfected state and the uservoluntarily performs another successful measurement cycle (for example,if, during the two hours after the prior successful measurement, shedisinfects her hands again), the re-test count down timer is reset.

Anyone in the vicinity of the doctor who can see the lights or LCD ismade aware of whether, according to the doctor's use of the badge, thedoctor's hands are disinfected or not. People who find troubling theindication that a person's hands are not disinfected can complain to theperson or to the employer, for example.

During the sensing cycle the doctor must keep her finger against thesensor for at least a certain period of time, say 60 seconds, to givethe sensor and the control circuit time to obtain a good reading. If thedoctor removes her finger before the end of the period, the controlcircuit remains in or switches to the not disinfected state and displaysthe word re-test on the LCD display.

If the doctor holds her finger against the sensor long enough tocomplete the sensing cycle, the results of the sensing cycle aredisplayed on the LCD and by lighting either the red light or the greenlight.

If the sensing cycle ends with a determination that the finger is notdisinfected, the doctor can try again to apply enough of the cleaner toher hands to satisfy the circuit and can test the ethanol concentrationagain. And the cycle can be repeated until the disinfected state isdetermined.

In addition to causing the green light to be illuminated and the LCD toshow clean, successfully completing an ethanol test also causes thecontrol circuit to reset a count down timer (not shown in FIG. 1) to apredetermined period (say, two hours) after which it is assumed that thebenefit of the ethanol treatment has worn off and the doctor's hands areno longer disinfected. When the timer times out at the end of thepredetermined period, the control circuit turns off the green light,lights the red light, and changes the displayed word from clean tore-test. The red light stays on and the word re-test continues to bedisplayed until a successful ethanol test is performed by the doctor.

As shown in FIGS. 2, 3, and 4, the badge 10 can be fabricated byassembling three layers.

A bottom layer 29 (shown schematically in FIG. 2) contains a printedcircuit 31 and components mounted on the circuit. The components includethe sensor element 30 of the sensor, two thin batteries 32, 34, amicroprocessor 36 (an example of the control circuit mentioned earlier),a clock 38 (an example of the timer circuit mentioned earlier that canbe used both for the measurement count-down timer and for the re-testcount-down timer), the two LED lamps 12, 14, and an LCD display device40. The detailed interconnections of the devices mounted on the bottomlayer are not shown in FIG. 2. The control circuit could be, forexample, a PIC microcontroller available from Microchip Technology, Inc.of Chandler, Ariz.

A middle layer (shown schematically in FIG. 3) is thicker than thebottom and top layer and provides physical relief for the componentsmounted on the bottom layer. The patterns shown in FIG. 3 representcutouts 43 or perforations in the middle layer.

A top layer 50 (shown schematically in FIG. 4) includes a non-perforatedand non-printed clear region 52 to permit viewing of the LCD display.Space is left for adding a photograph and other information as show inFIG. 1. A perforated region 54 provides openings for passage of ethanolvapors into the badge and two perforations 56, 58 on opposite sides ofthe perforated region 54 accept the conductive electrodes that are usedto detect the presence of a finger.

As shown in FIG. 5, the arrangement of the three layers in the vicinityof the sensor provides a sensing chamber 56. Ethanol vapors 55 pass fromthe finger 53 through the holes in perforated region 54 (which is shownas narrower than in FIG. 4) and into the chamber. Within the chamber isa tin oxide sensor element 30 (which includes an integral heater). Thesensor element is connected by wire bonded connections 61 to circuitruns 59 on the bottom layer of the badge. The heater heats the vaporswithin the chamber and sensor element measures the concentration ofethanol.

Tin oxide sensors are small, low cost, and relatively low in powerrequirements. An example of a tin oxide ethanol sensor is the Model TGS2620-M available from Figaro USA Inc. of Glenview, Ill., although othersensors available from other vendors could be used.

The sensor includes an integral heater and four connections, two for thesensor element, and two for the heater. By wiring a resistor in serieswith the element and measuring the voltage drop across the resistor, thecontrol circuit can determine the amount of current flowing in theelement and hence the resistance of the element which will vary withethanol concentration.

Tin oxide sensors with heaters are subject to a so-called initial actionthat occurs when the sensors are not energized for a period and then areenergized. The resistance of the sensor drops sharply during an initialperiod of energization, whether gases are present in the surrounding airor not. The longer the period of unenergized storage (up to about 30days), the longer the period of the initial action. Therefore using tinoxide sensors in the badges requires a trade off between powering theiroperation for a period longer than the initial action but not so longthat the energy drain caused by measurement cycles reduces the lifetimeof the battery to an unacceptably short period. Experiments suggest thatif the user keeps her finger in contact with the sensor for at least 20or 30 seconds, the sensing of ethanol then begins to dominate theinitial action and permits detection of the ethanol concentration. Otherapproaches may provide a shorter initial action (such as applying alarger voltage for the first few seconds of operation and then thenormal voltage after that).

The badge provides a simple, effective, portable, and inexpensive way toconfirm that the ethanol treatment has occurred no longer than, say, twohours ago, which likely means that the hands remain disinfected. Noother external equipment is needed. The disinfection condition isapparent to anyone in the vicinity of the doctor, including patients,supervisors, regulators, and peers. The social pressure associated withbeing identified easily as not having disinfected hands is an effectiveway to improve the frequency and thoroughness of cleaning The systemdoes not force the doctor to comply. Compliance with cleaning rules andpolicies may remain less than perfect using the badges, yet it is likelythat the compliance will improve significantly. Any degree ofimprovement translates into reduced costs and injuries now associatedwith hands that have not been disinfected.

Although we sometimes have referred to use of the system by a doctor, itis also useful for a wide variety of other people, including otherhealth care workers, clean room workers, and guests, consumers, vendors,employees, and other parties involved in any kind activity in whichcleanliness of the hands or other parts of the body is important.

For example, although a simple matching of a measured ethanolconcentration against a threshold can be used to determine simplywhether the state should be disinfected or not disinfected, it is alsopossible to provide a more complicated analysis of measuredconcentration over time and a comparison of the measured concentrationagainst dynamically selected thresholds.

More than two states would be possible, for example, to denote differentlevels of disinfection or to denote that longer periods of time mayelapse before another measurement is required.

The length of time before a first measurement is considered stale andanother measurement is required need not be based on an estimate of howlong the ethanol on the skin will be effective, but can be based on anarbitrary period such as every hour.

The degree of accuracy and repeatability of the measurement of ethanolconcentration may be traded with the cost and complexity of thecircuitry needed to do the measurements. In some examples, the goal neednot be to assure that the user's hands are thoroughly disinfected at alltimes. Rather, if the system encourages more frequent and more thoroughcleaning to any noticeable degree, great benefits will result. Thus avery simple system may be quite useful and effective even though it mayallow some users to cheat and may fail to determine the state accuratelyat all times.

Additional lights and displayed words may be used for a variety ofpurposes. The approach of the end of the disinfected period could beindicated by a yellow light to alert the user that a cleaning would soonbe needed.

The lights and LCD display could be supplemented with or replaced byaudible alerts for all functions or some of them.

In some examples, not all of the circuitry need be mounted in a singlebadge. Some of the circuitry could be located in a different piece ofequipment. For example, a sensor used in common by many people may bemounted on a wall and convey (say by wireless communication) themeasured concentration of ethanol to the badge, which would thendetermine the state and indicate that state through lights and on theLCD. By separating the two, the badge could be lower cost, the sensorcould be more complex and accurate, and the sensor could be located atplaces where the disinfectant solution is dispensed. Fewer sensors wouldbe needed.

Each badge could itself be split into two components that communicatewith each other wirelessly or by wire. For example, a sensor modulecould be located in the user's pocket, while the badge contains only thelogic circuitry.

The cleaning agent that is being measured need not be limited to ethanolbut could include combinations of ethanol with other materials or othermaterials in the absence of ethanol; an appropriate sensor for the othermaterials would be used.

The badge could include clips, hook and loop fasteners, chains, pins,ribbons, and belt loops, and other devices to hold the badge on theuser.

The device need not take the form of a badge but could be an ID devicethat attaches to a belt, a lapel, any other article of clothing, andother parts of the body including an arm, a leg, or a neck.

Instead of integrating the badge, sensor, and indicators in one unit,the badge could be an already existing badge of the kind used inhospitals, for example, to identify employees. Such badges often includenames, photographs, and magnetic stripes or bar codes that can be swipedon readers. A shown in FIG. 8, the device 80 could take the form of aholder 82 in which the existing badge 84 could be held. The device wouldthen contain all of the other elements except those that appear on thebadge. Arranging for a separate badge and badge holder has a number ofadvantages. The badge can be removed and used and swiped independentlyof the device. The badge can be replaced separately without requiring areplacement of the device electronics. Existing badge equipment andtechnology can continue to be used. In some examples, the badge could bedesigned to couple electronically to the holder using, for example, RFIDtechnology with an RFID element 85 in the badge and an RFID transceiver87 in the holder. When the badge is placed in the holder, the holderrecognizes the identification of the user and other information.

In some examples, the badge, the holder, and the RFID transceiver 87could be arranged differently. For example, the RFID transceiver couldbe located on a different device worn by the user while the badge couldremain mounted on the holder.

The badge could be powered by photovoltaic cells using ambient lightinstead of a battery.

Although two different lights could be used to indicate the disinfectedand not disinfected conditions, a single light that can change colorcould also be used, saving cost and space.

Because the ethanol sensor has a lifetime that is limited by the numberof test cycles, the badge can include a circuit that counts the numberof tests performed and illuminates a warning light or provides someother indicator when the sensor is reaching the end of its useful life.

Other types of ethanol sensors can be used. One such sensor comprises aceramic chip but is considerably more expensive than the sensorsdescribed earlier.

Although ethanol and an ethanol sensor form the basis of some of theexamples described here, other disinfectants (for example, trichlosan)may also be used provided that effective sensors are available for them.

In general, in addition to triggering a change in state of the badgeafter a period elapses, it is also useful to maintain a count of thenumber of times a person has run a test (sometimes called the number oftaps) using the sensor in a given period of time. The badge can containa counter that keeps track of the number of taps and determines thecount per 24 hours. This number can then be reported to the person'semployer or to regulatory agencies as evidence of good cleanlinesspractices in an institution. For reporting purposes, the number ofcounts can be communicated to a reader by RFID technology, or any othercommunication technique.

The sensor and indicators need not be associated with identificationinformation but could be provided in a device the sole purpose of whichis to measure the concentration and provide an indication of it.

The device can be used in non-health care environments in which handcleanliness is important or expected.

In a health-care environment, the device could be used by anyone who isproviding services as well as by patients and their families or friends.

Information about the frequency, timing, and results of measurementsperformed historically by the user can be stored on the badge.

Many additional functions could be added to the badge by increasing thecapacity of its processor, memory, displaying, communications ability,and user inputs features.

In other examples of a cleanliness sensing badge 200, as shown in FIGS.10, 11, 12, 13, and 14, a battery 202, a circuit board 204, a sensor206, a multi-color LED 207, a two-dimensional display 209, and amomentary on switch 208 are mounted within two halves 210, 212 of ahousing. To reduce the chance of contamination of or damage to thecomponents on the inside of the housing, sealing elements can beprovided along the seam between the two halves and at the openings inthe two halves through which each of the LED, the switch, and thedisplay are mounted.

As shown in FIG. 14, the components of the sensing badge include a CPU220 having a flash memory (Microchip part 18F6720) to control (a) thedisplay 209 (Varitronix part COG-ZBD9696-02) through I/O lines 222, (b)an alcohol sensor 224 (Figaro part TGS2620) through control outputs 226,228, and A/D input 230, (c) a piezo speaker 231 through outputs 234,236, (d) the two-color LED 207 through outputs 238, 240, and (e) anexternal EPROM (Microchip part 24FC256) 239 through an I/O bus 242. TheCPU 220 also receives information from the switch 208 and communicatesbidirectionally through a voltage level shifter 244 (Maxim partMax3001E), an RF transceiver 246 (Chipcon part CC2420), a balun circuit248, and an antenna 250 with transponders, base stations, and possiblyother external devices 251. The voltage level shifter shifts the DCvoltage level of signals sent back and forth to the CPU from the 5.0volts level used by the CPU to the 3.3 volts level used by thetransceiver, saving power.

Power for the circuitry is provided by the battery 202 through a DC/DCconverter 252 (Maxim part Max1677) and a voltage regulator 254 (TexasInstruments part TPS77033).

The alcohol sensor 224 includes a sensor element 225 and a heater 227.The resistance of the sensor element changes in the presence of alcoholvapor by an amount that relates to the concentration of the vapor. Bypermitting alcohol vapor from a person's finger to reach the sensor andby using an appropriate test protocol, the relationship of theconcentration of the vapor to a threshold can be determined and used toestablish a disinfected or not disinfected state of a user's hands. Theresistance of the sensor element 225 is measured as an analog voltage atthe A/D input of the CPU. If the sensor element remains dry, theresistance of the element in the absence of alcohol will be subject tovery little drift. However, if the sensor element is exposed to water orwater vapor, the resistance will change substantially. For this reason,in a typical use of the sensor element 225, the heater is energized fora period to dry the sensor element before a measurement is taken. Thus,a time delay must occur from the time when a measurement is desireduntil the time when the measurement is completed.

To eliminate the time required to heat the sensor element at the timewhen a test is to be started, the resistance of the sensor element iscontinually monitored. If the drift in the resistance of the elementoccurs more slowly than a background drift rate, indicating that thesensor element has remained dry, no action is taken and the sensorelement is considered to be in a standby mode. Conversely, if theresistance drift is comparable to what would be expected when watervapor is present at the sensor element, the CPU drives the heater in aheating mode to dry out the sensor element. As soon as the resistancehas returned to the expected dry value, the heater is turned off and thesystem returns to the standby mode.

When the sensor element is in the presence of alcohol vapor, such aswhen a person with disinfected hands places a finger near the monitor,the resistance of the dry sensor element shifts substantially,indicating a presence of alcohol vapor. This causes the CPU to enter atest mode in which a determination is made whether the concentration ofthe vapor exceeds a threshold that indicates disinfected hands. Once thetest is completed and related actions are taken by the CPU in responseto the result, the CPU returns to the dry mode. The heater is driven bythe CPU output through the gate of a transistor 256. To detect theresistance of the sensor element, the CPU drives the sensor elementthrough the gate of a transistor 258 and the voltage level at a node 260is the analog input to the CPU.

In this way, the sensor is always available for a test measurementwithout requiring a heating cycle and the user can perform a test simplyby putting her finger near the sensor element without requiring an onswitch to be activated. Nevertheless, in some implementations, a switchcan be provided that can be pressed by the user to initiate the testmode.

The program used by the CPU to operate in the standby mode, the heatingmode, and the test mode, is stored in the CPUs flash memory, while dataneeded to operate in those modes, data derived from measurements of theresistance of the sensor element, and other information can reside inRAM or external non-volatile EPROM.

The data can be stored in and retrieved from the EPROM by the CPU onbehalf of itself and on behalf of external transponders, base stations,and other devices for a wide variety of purposes. Data can be stored atthe time of manufacture, at the time of registration of a user, duringoperation of the monitor, or at any later time.

The data in the EPROM can include calibration information about theempirical relationship of the resistance of the sensor element to thepresence of different concentrations of water vapor, and of differentconcentrations of alcohol.

The data contained in the EPROM includes calibration data, thresholdvalues, and other data useful in the operation of the alcohol sensor,data about a user of the badge, data used for the LCD display, data todrive the piezo speaker, data derived from measurements of the sensorresistance, historical data about the times and results of measurements,and information useful in communicating with external devices.

The calibration data for the alcohol sensor can include empirical dataor tables that represent the expected resistance of the sensor elementassociated with various levels of water vapor or alcohol. The thresholdvalues could include a threshold value for resistance that indicates thepresence of water vapor, a threshold value that indicates the presenceof alcohol vapor, and a threshold value that indicates that theconcentration of alcohol vapor exceeds a value associated withdisinfected hands. The data for the alcohol sensor can also includeinformation about rates of change of resistance that may be associatedwith the introduction of water vapor or the introduction of alcoholvapor that will enable the CPU to determine when to switch modes amongthe standby mode, the heating mode, and the testing mode. The datastored in the EPROM may also include drift information that indicates anexpected rate of drift of the resistance during standby mode over time,and expected rates of change of resistance when water vapor and alcoholvapor are present. The sensor element has a useful life that may beassociated with the number of testing cycles for which it has been used.The EPROM may store information about the number of expected cycles anda counter that indicates the number of actual cycles.

During operation, data may be stored in the EPROM that includes a recordfor each test performed, including the starting and ending time, thestarting resistance, the ending resistance, an indication of the resultof the test (not disinfected, disinfected, inconclusive), whether thetest result has been reported to an external device, and whether thetest was initiated by pushing the on button or simply by touching thefinger to the badge. The EPROM may also include data useful in perform adiagnostic test of the sensor element by applying a certain voltage andcalculating the resulting resistance values over time.

The algorithm that is stored in the EPROM and run by the CPU withrespect to the sensor element could include the following sequences.During initialization of the badge (e.g., when the badge is firstpowered up), the sensor heater may be powered up to heat the sensorelement. Then the sensor element may be energized to +5 Volts and thevoltage at the A/D input can be read by the CPU. The heater may be kepton until the voltage measurement from the sensor element becomes stable(slope is essentially flat), indicating that the heating mode is done,the sensor element is active and dry, and the badge may enter thestandby mode. The heater and sensor element are then de-energized andthe sensor element is allowed to cool to ambient temperature. Then theheater and sensor element are re-energized for a calibration test. Aftera predetermined test period has elapsed (say, two seconds), the voltagefrom the sensor element is measured and the value is saved as thecalibration reference value indicative of the baseline dry state.

When the on button is pressed, the CPU energizes the heater and sensorelement for a fixed test cycle period (say two seconds). If the measuredvoltage representing the resistance of the sensor element is a certainpercentage (say 20%) higher than the baseline dry state reference value,the CPU determines the presence of enough alcohol to indicatedisinfection. Otherwise the CPU determines no disinfection. In someexamples, instead of de-energizing the alcohol sensor after the initialcalibration, the CPU may power the sensor element continuously (orfrequently but intermittently) and make continuous (or intermittent)measurements of resistance. As an alternative to pushing the on button,when a sharp shift in resistance is detected, the CPU may assume thatthe user has placed her finger near the sensor element and wants toinitiate a test. In addition, if the resistance level changessufficiently to indicate presence of water vapor, the CPU can initiate aheating mode.

To compensate for drift in the sensor, the CPU may periodically measurethe voltage output from the sensor element using the steps described fora button press above. If the measurement reflects only a modest drift inthe sensor resistance, then the CPU would substitute the currentmeasurement for the previously stored one. If the drift were significant(perhaps more than one percent different from the previous measurement),the CPU would enter a recalibration mode using the steps described forthe initial startup.

In addition to running the algorithm that controls calibration, heating,testing, and standby modes, the CPU may run a process, stored in theflash memory of the CPU, that controls communication of the badge withexternal devices.

The communication process may perform a wide variety of functions thatare initiated either by the CPU itself or by the external device.

In one function of the communication process, the CPU continuallywatches for a signal from the transceiver indicating that the badge iswithin communication range of an external device, such as a transponder,a base station, or another device. If so, the CPU may execute a routineto fetch data from the EPROM and communicate it to the external device.The information to be fetched could include the identity of the user ofthe badge, the results of calibrations of the sensor, calibrationvalues, battery life information, the number of tests performed sincethe prior upload, and the results of all of the tests performed in theinterim, including all or selected portions of the data stored. Asexplained below, the CPU may have stored data in the EPROM indicatingthe successive locations in a building or a campus at which the badgehad been recognized by external communicating devices, and the upload ofdata could include the data represent the successive locations. When atest has been performed at one of the locations, the association of thelocation with the test may also be uploaded.

The determination of what data is to be uploaded could be made by theCPU or by the external device to which the data is to be uploaded.

In addition to uploading data from the badge to the external device, insome examples, information and commands may also be downloaded from theexternal device to the badge. The data to be downloaded could includeupdated calibration values, updated threshold values, updatedidentifiers, information to be shown on the display of the badge, arefresh of prior test results and data, and other information. Thecommands could include instructions to turn the badge on, or off, toperform a test and return the results, to upload the test results fromprevious tests, to purge the EPROM of prior test results, to control thelighting of the LEDs or the information shown on the display, to triggerthe speaker, to reconfigure the transceiver, to reboot the CPU, andother commands.

The CPU may continually maintain information about the cleanliness stateof the user that is based on current and historical tests performedeither on the badge or on another device (for example, the results ofalcohol tests performed on a wall mounted tester could be communicatedto the badge and used for that purpose). The badge will switch from thedisinfected state to the non-disinfected state after a predeterminedperiod that can be stored in the EPROM and updated based on empiricaldata about the duration of effectiveness of an alcohol cleaning of thehands.

In addition, the badge can be forced by a command from an externaldevice to switch from a disinfected state to a not disinfected statewhen the badge is in communicating range of the external device. Thisfeature can be used by a manager of a building, a space, or a campus, toenforce a fresh hand cleaning regimen on users at certain locationswhether or not they are currently in a disinfected state.

For this purpose, external devices may be located in places where thehand cleaning regimen is to be enforced and may continually broadcaststate changing commands to any badges that come within range. Forexample, a transponder may broadcast a “switch to not disinfected state”command constantly or at times when a badge is detected nearby. Inresponse to receiving the command, the badge will switch states andaccordingly, update whatever warning signals correspond to a disinfectedstate may be sent, including switching the LED from green to red,changing a message that is shown on the LCD display, and changing thesound delivered by the speaker. The change in state will stronglyencourage the badge owner to wash his hands and test them in order toswitch the state back to disinfected.

For example, the manager of a facility may want to enforce thecleanliness regimen at all bathrooms in the facility. External devicessuch as transponders can be posted at the entrances to all bathrooms (orto clean rooms in the facility, or to operating rooms), causing thebadge of every person who enters the bathroom to be switched to a notdisinfected state. In order to switch the badge back to disinfected, theuser must wash with alcohol and successfully test her finger. Theenforced regimen can be managed statically, simply by the placement ofthe transponders in desired locations that automatically broadcaststate-switching commands. In some examples, the control of the regimencould be dynamically altered, if the external devices that cause theswitching of the state are in communication with a central controller,for example, through an IP network. In such a system, the centralcontroller could be configured at one time to cause certain selectedtransponders to flip states of badges and at another time to cause adifferent set of selected transponders to flip states of badges.

For example, a hospital administrator may wish to enforce the cleaningregimen in one wing of the hospital on one day and in another wing onanother day. Or the regimen may be enforced during a night shift but notduring a day shift. In some examples, the facility may decide to flipthe states of all badges at all locations at one time.

The external devices may include stand alone devices such astransponders that are passive one-way transmitters of commands, do notreceive any data in return and are not connected to any other devices.In some examples, the external devices could also have two-way datacommunications capabilities and/or could be connected to other devicesthat have additional capabilities. The external devices could bededicated to functions associated with the badges or could be devicesthat have other functions for other purposes.

The external devices could include several kinds in one system includingtransponder, wall-mounted test devices, base stations that would servemultiple transponders, and central stations that would communicatemultiple based stations and/or transponders. The communications amongtransponders, monitors, base stations, and central stations can occurwirelessly or by wired connections and by peer to peer communication orin a client server mode.

In addition to triggering state switches in the badges and communicatingdata about alcohol tests performed in the badges, the monitoring systemcan also track the locations and succession of locations of badgeholders. In some examples, when badges communicate their identifierinformation to external devices the information is passed to a basestation and/or to a central station. In this way, the central stationcan be aware of recent locations and the history of locations of allbadge holders. The cleanliness state of the badge holders can then beassociated with the locations and action can be taken if necessary. Forexample, if a badge holder repeatedly enters bathrooms in the course ofa day but never washes, the administrator of the facility can confrontthe person directly. More generally, the badge state history ofindividuals or groups, or all badge holders can be stored and reported,and analyzed.

Studies of selected groups may be performed. For example, a study canfocus on the cleanliness habits of surgeons as compared to nurses. Forthis purpose the party performing the study can control the flipping ofstates of the badges and record and study information about testing doneby the badge holders over time.

The history of which badge holders were in which locations and in whatcleanliness states when at those locations may be tracked and analyzedand be used to provide useful information associated with specificevents. For example, suppose a patient or other person in a hospitalcontracts an infection that is normally thought to be transmitted bytouching or close proximity. If the patient's room was a locationprotected, for example, by a state-switching transponder, the history ofbadge locations could indicate which health care workers were inproximity of the patient during a period considered to be when theinfection was transmitted. This could enable identifying individuals whomay be carriers of infection for corrective action, for example.Correlation of infections contracted by multiple patients withcleanliness states and locations of badge holders could facilitateidentifying a carrier.

To control the operation of the monitor system, each base station and/oreach central station can include a graphical user interface, forexample, an interface presented in an Internet browser window.

Referring again to FIG. 14, the LCD display 209 can be of a kind thatprovides a stable display even when unpowered. In such a display, poweris required to change the states of the pixels of the display, but oncethe pixels have reached a stable state, they will remain in that stateeven after the power has been removed. Such displays are available in astwo-state “black and white” devices, and it is expected that gray scaleand color LCD panels with the same unpowered stable state feature willsoon be available. One advantage of such a display is that the socialpressure aspect of the system can be brought to bear even if the userattempts to remove the battery or otherwise disable the device. Such adisplay also reduces the use of battery power significantly. Otherfeatures described here (for example, the use of a lower powered 3.3volt transceiver and the ability to operate in a standby mode) alsocontribute to reduced battery load.

The information to be shown on the display could include the name,identifying number, and picture of the user of the badge (based on astored image), the cleanliness state of the user, the history of thecleanliness state, and the state of the badge and its operation. Thedisplayed information could be controlled by the CPU or in part by theuser of the badge, or by the facilities manager.

The communication protocol in some examples is the Zigbee protocol (IEEE802.15.4) which requires relatively low power, operates at 2.4Gigahertz, is license-free, and operates at relatively low telemetryrates.

Referring again to FIGS. 10 through 13, the front of the badge includesa sensor access grid 300 in the form of a round configuration of linearslits that allow alcohol vapors to pass into an enclosed sensor chamber302 formed within the housing. The sensor chamber includes a tubularchannel 304 in which the cylindrical outer wall of the alcohol sensorcan be held with the end face of the sensor aimed in a directionparallel to the front surface of the badge (rather than aimed in thedirection of the sensor access grid). Alcohol vapors can follow the pathof arrow 306 into the chamber 302 where it can touch the sensor elementface of the sensor. Eventually the incoming vapor can exit at rightangles through a vapor exhaust vent 308 on the back half of the housing.The intake grid and the exhaust vent are positioned and oriented so thatforeign materials (water or other liquids, for example) that strike theouter faces of the housing cannot easily reach the surface of andcontaminate the sensor element. Other features of the housing seal theperimeters of the two halves and the holes through which the on switch,the display, and the LED project.

In some examples, instead of (or in addition to) storing the user'sidentity information in the EPROM of the badge, the information (andother information about the user) can be derived using RFID technologyfrom an RFID chip 318 that is part of an existing identification badge316 issued by the facility to the user for other purposes. In theseexamples, the badge could be extended 314 at one end to accommodate thebadge.

The piezo speaker can be used for a wide variety of functions. Onefunction is to provide an audible indication of a cleanliness state ofthe user. By storing appropriate audio clips in the EPROM and playingthem back through the speaker, a happy or upbeat sound could be playedbriefly when a successful test is completed and an unhappy or grumpysound could be played when a test has failed. In the case of a failedtest, the grumpy sound could be repeated at intervals (say severalminutes) and the volume of the sound could be increased and theintervals decreased over time so that the social pressure to wash thehands and conduct a successful test becomes irresistible.

In addition to a display, an LED, and a speaker, the badge could includea vibration element to alert the user when the safe disinfected periodis near an end or has ended, for example.

As shown in FIG. 6, in some examples, a monitor 70 could be mounted on awall 72 of a space 74, such as a bathroom. The monitor could contain aradio frequency transceiver 75 that would cooperate with radio frequencyidentification (RFID) elements contained in badges of users. Using RFIDtechnology, when a person wearing a badge passes near to the monitor,the monitor could use RF communication to determine that the person ispresent and to fetch information from the badge about the person'sidentity (and other information as discussed later). The monitor couldalso send an instruction to the badge to cause the badge to reset itselfto the not disinfected state. Communication technologies other than RFIDcould also be used to detect the presence of the user and to communicateinformation between the monitor and the badge or other elements worn bythe user. The element worn by the user could be one that identifies theuser or one that does not identify the user.

When the person wearing the badge enters the bathroom, or any othermonitored space such as a patient room, or a surgical theater, thetriggering device sends a signal to the badge that causes the badge toenter the not disinfected state and light the lamp that indicates thatstate. This triggering will encourage the user to disinfect his handsbefore leaving the bathroom or before proceeding further into themonitored space in order to avoid the social disapproval associated withleaving the bathroom with the red light on. In these examples, thebadge's state could be forced to change to the not disinfected stateregardless of how much time has passed since the most recent successfultest using the badge sensor. The user's status can be reset to thedisinfected state by the user cleaning his hands and testing them.

As shown in FIG. 7, a hand cleanliness monitor 70 could include not onlyan ethanol or other sensor 106 but also a presence detector 108 and oneor more indicators 110 of hand cleanliness with respect to one or morepeople who have entered the space. One of the indicators 112, whichcould be broadly visible to people in the space (for example, if it isplaced on an interior wall of a room) or people outside the space (forexample, if it is placed on an interior wall of a room) or both, couldturn from green (indicating that all people in the space are believed tohave disinfected hands) to red when a person is detected as entering thespace. In that case, the red light would indicate to viewers that aperson whose hand cleanliness state is unknown and assumed to be notdisinfected has entered the space.

The person entering the room could cause the light to turn from red backto green by touching the sensor (assuming his hands bear enough ethanolto imply a disinfected condition) or by first cleaning his hands andthen touching the sensor.

In some examples, the monitor could be placed on in interior wall of apatient's room. Whenever anyone enters the room, including health careworkers, the patient, or guests, the monitor would indicate a possiblynot disinfected condition until someone touches the sensor and causesthe red light to turn green. Social pressure of people in the room, whowould observe the red light would help to enforce good cleanlinesshabits on every person entering the room.

The parts of the monitor need not be included in a single integratedwall unit. For example, a portion of the monitor that detects that aperson has entered or left a space could be a separate system, includingan existing system, that would exchange the information with the monitoras needed. The indicators could also be located separately from themonitor to make the lights visible to many people even though themonitor is located near an entrance to or exit from a monitored space.The sensor, too, could be located separately from the monitor. Forexample, the badge sensors could provide the re-test information to themonitor.

In some examples, an entire building could be monitored by providingmonitors on the walls at all entrances to the building. In addition tothe social pressure associated with public display of the notdisinfected condition, an employee or automated gate at each entrancecould require that the person entering either prove that his hands aredisinfected by using the sensor either upon entry or after using adisinfectant available at the entrance.

A variety of spaces could be monitored, including bathrooms (or otherlocations where disinfecting is especially important) and changing areasin hospitals or food processing facilities, for example.

In some examples, the monitor could include circuitry that would detect,in other ways than described above) a presence of one or more peoplewithin a space (whether or not the people have entered or left thespace), would determine a cleanliness state of hands of the peopledetected as present, would include circuitry to report the cleanlinessstate.

A publicly viewable monitor used to indicate the disinfected conditionfor people within a space can facilitate social pressure being appliedby people in a room to people who enter the room even without themonitor having any information about the identity of a person enteringthe room. In addition, the monitor may include or be part of a systemthat includes devices to determine who has entered a space and tocorrelate that information with a person who then uses the sensor toindicate that his hands have been disinfected.

For example, the person entering the room may carry a badge (of the kindissued by a health care facility) that uniquely identifies him andincludes a bar code, a magnetic stripe, an RFID element, or anotherdevice that can be read by a reader 114 (for example, the RF transceiver75 in FIG. 6) that is on the monitor or mounted separately on the wall.Depending on the technology, the user's badge could be read from adistance or be swiped on a reader. When the person enters the room, hispresence and identity are detected. At the time when he successfullycompletes a measurement by the sensor indicating that his hands havebeen disinfected, his identity is read again and compared with theidentities of people who have entered the room and not been determinedto have passed a measurement for disinfected hands. Only when all of thepeople who have entered the room have passed the test will the red lightbe switched to green.

An enterprise could issue temporary identification cards to every personwho enters a building or other space and does not already have anidentification badge for use with the system.

A variety of other techniques could be used to identify the personentering a space, including detection of biometric information (such asa voice print or a finger print or a facial print) or requiring a personto enter an identification code on a keypad 116 on the monitor. Theperson could enter the identification both upon entering the room (insome cases as a trigger for a locked door or other entry gate) and uponpassing a disinfection test using the monitor. In some implementations,it may be possible to identify a person using a fingerprint detectiontechnique at the same location on the monitor and at the same time asthe disinfection test is performed. Other techniques could also be usedto assure that a successful test is accurately correlated to anidentifiable person.

The monitor can also include circuitry that keeps track of how manypeople are in the space (for example, by also detecting when someone hasleft the space). When the oldest successful disinfection test (amongtests that number as many as there are people still in the room)occurred more than a predetermined period (say 2 hours) earlier, themonitor can time out and change the green light to red until someone inthe room successfully tests his hands again.

In these examples, and others, it is possible for people to deceive themonitor, for example, by having one person in the room repeatedly testhis hands positively on behalf of other people in the room. However, asindicated earlier, at least in some examples, the social pressureassociated with the public display of the disinfection state of thespace and the shifting of green to red in certain situations, may besufficient to significantly improve the frequency and quality of handcleaning among people in the space.

Other arrangements could be used to reduce the degree and nature of thedeception that may be possible and to increase the ability of amonitoring system to track and report the performance of identifiedpeople or groups of people in maintaining hand cleanliness. Some sucharrangements would use the unique identifiers associated with differentpeople to track their performance.

For example, the wall monitor could include a processor and software totrack individuals who enter and leave a room based on their uniqueidentifiers and correlate the identities with tests that are performedsuccessfully. The monitor could then control the red light and greenlight based on the successful testing of hand cleanliness by eachindividual in the space at least as often as some pre-specified timeperiod (say every two hours). By including a small display 120 on theface of the monitor, the person whose hand cleanliness requiresre-testing can be identified by name or identifier or some otherindicator. In this way, each of the people in the space can be alertedfrom time to time of the need to re-clean, and re-test and everyone inthe space can know who needs to do so.

Such a monitor could be used in conjunction and cooperation with wornbadges, for example, of the kind discussed earlier. For example, usingRFID or wireless or other kinds of communication capability in themonitor and at least some badges, the monitor and the badge couldcommunicate, exchange information, control actions, and make reports,all in a wide variety of ways.

In a simple example, the monitor could cause the light on a badge toswitch from red to green at the same time (or different times) as thelights are switched on the monitor, to indicate to others in the spacewhich person in the space needs to re-clean and re-test. A successfultest performed on the badge can be reported to the monitor for use, forexample, in the same way that a test on the monitor would be used.Conversely, the monitor can report to a badge a successful (orunsuccessful test) performed on the monitor by the owner of the badge.More generally, the badges and monitors in one or more spaces cancontinually be synchronized to store common information about tests bythe owner of the badge and to cause common indications of thecleanliness state of the badge owner to be given by both the monitor andthe badge.

As a person moves around in a building that has more than one monitoredspace, the monitors and the badges will together in that way maintaincurrent information and provide current indications of the cleanlinessstate of the badge owner.

As shown in FIG. 9, although this co-operative maintenance ofinformation and reporting can be done informally and by ad hoc action ofdifferent pairs of badges and monitors over time through a building,additional functions and better performance may be achieved by arrangingfor a portion or all of the monitors 130 in a building 132 or campus ofbuildings 134 to be interconnected by a wired or wireless communicationnetwork on a peer-to-peer basis or with the co-operation or control of acentral server 136 or a distributed set of central servers 136, 138,140. The central server or servers may be servers already used for afacility to provide communication and manage the control of other kindsof devices scattered throughout the facility or the reporting ofinformation from other kinds of devices.

The monitors, the badges, and/or the central server or servers mayinclude memory or mass storage 144 that contains a database 146 or otherorganized information about the permanently or temporarily registeredpeople who have access to a building or space. The database can storeinformation that is associated with individuals and information that isstatistically related to groups and subgroups of the individuals.

In some implementations, an individual badge can maintain a smalldatabase of information about a complete history of an individual'scleanliness testing beginning at the time when the badge was firstissued, or at some later time. Or a rolling set of data ending at thecurrent time may be kept. The data may catalog every instance when theuser tested the cleanliness of his hands, the result, the time of thetest, and the parameter values that were produced by the sensor in thetesting. When the badge is able to communicate with monitors indifferent spaces or subspaces, the badge database may also track theplaces in which each of the tests was performed, which other people werepresent in the space when the tests were performed, and otherinformation. Information in the badge database can be uploaded to one ormore monitors using the communication links to the monitors, or may beuploaded from the badges directly to a central server using specialbadge readers located in one or more places in the facility.

Each monitor can maintain a database of information using informationfrom badges of people with whom the monitor has interacted andinformation from other monitors in other spaces (for example, contiguousspaces). The database of a monitor could track every time a person hasentered a monitored space and every time she has left the space. Thedata could include the time of entry, the time of exit, the space inwhich the user was most recently monitored, the time between entry intothe space and when a re-test was performed, the results of the re-test,the number of re-tests performed in the room, the identities of otherpeople in the room at the time of re-test, and a wide variety of otherinformation.

If a person leaves a monitored space 131 and enters a monitored space132, the monitors in the two spaces could be arranged to communicate sothat the monitor in space 132 need not require a re-test if a re-testhad been done in space 131 within a pre-specified earlier period.

When the monitors and/or badges are networked with a central server, thecentral server can use information provided from the monitors and/orbadges to track the overall cleanliness testing activity of all of themonitored people in all spaces that are networked.

The central server could maintain a database 134 that could includedetailed historical information and statistical summaries ofinformation. The information could track every time any of the monitoredpeople enters or leaves a monitored space, the number of times and thetimes at which re-testing has been done, the results of each re-test,the routes of the people moving through the building or campus, whetherthe people are wearing their badges, whether they used their badges orthe wall monitors to re-test cleanliness, and a wide variety of otherinformation.

The central server can use software 140 running on the server or serversto analyze information stored in the central database or the databasesof one or more of the badges or the monitors. The analyses can addressthe performance of different groups on cleanliness, the correlation ofcleanliness to location, the correlation of demographics (age, gender,geographic location) with cleanliness, the impact of training,monitoring, and other actions on the cleanliness performance, and timedependent changes by individuals, groups, and subgroups of cleanlinessperformance.

In addition to monitoring and analyzing information about cleanlinessperformance the central service can provide reports that are useful toor required by the party that operates the building or campus, otherinstitutions, liability carriers, and governmental bodies that regulatecertain aspects of the performance of the party and the individualsemployed by the party. For example, governmental agencies may requirehospitals to assure that hospital employees are disinfecting their handsmore often than a certain number of times a day and to report failuresto meet that requirement. Reports may also be given to individuals beingmonitored to groups of individuals, to their supervisors, and to others.Reporting to individuals can be done by email. For example, a doctor whois not disinfecting his hands often enough would periodically be sent anautomatic email urging him to improve his cleanliness practices.

The physical housing used for the monitor could be much smaller than thebadge shown in earlier examples and could be used in other environments.For example, a badge in the form of a ring could be used for a nanny. Atthe end of the day, when the parents of the nanny's charge return home,the ring would immediately indicate whether the nanny had washed herhands at least every two hours during the day. In another example, theprinted circuit board used to implement a badge can be a stacked printedcircuit board to provide a more compact form.

In some implementations as illustrated in FIGS. 15A and 15B, a system400 including badges 410 and monitors 412 can be configured to promptindividuals (e.g., health-care providers) to sanitize their hands bothon entering and exiting a specific space (e.g., a patient's room).

As shown in FIGS. 16A and 16B, each of the monitors 412 can include anouter casing 450. A PLC chip 452, a motion detector 454, and atransceiver 464 are disposed within the outer casing 450. Asillustrated, the motion detector 454 can be a programmable infrareddetector including an infrared sensor 458 mounted on a motion detectorboard 462 and a trigger light 456. The trigger light 456 is placed toemit infrared radiation through an opening in the outer casing 450. Asensor shield tube 460 extends from the motion detector board 462 to anopening (e.g., the same opening through which the trigger light 456emits infrared radiation or another opening). The sensor shield tube 460can reduce or prevent direct transmission of infrared radiation from thetrigger light 456 to the infrared sensor 458. Rather, as a person orobject crosses in front of the opening, some of the infrared radiationemitted by the trigger light 456 is reflected by the person or objectand travels through the sensor shield tube 460 to contact the infraredsensor 458. In some embodiments, other motion detectors such as, forexample, ultrasonic motion detectors can be used. The monitors can bebattery-powered, can include photovoltaic cells, can be directly wiredinto a building's electrical system, and/or can be adapted to be pluggedinto standard wall sockets.

The motion detector 454 is electronically coupled to the PLC chip 452.Upon receipt of a signal from the motion detector 454 indicating thatthe infrared sensor 458 has detected infrared radiation, the PLC chip452 actuates the transceiver 464 to send a signal configured to bereceived by badges 410. For example, the signal can include informationidentifying the transmitting monitor 412.

As shown in FIGS. 15A and 15B, the monitors 412 can be located neardoorways 414 or other thresholds (between spaces) to be monitored. Inresponse to motion in a doorway 414, the monitor 412 placed near thatdoorway 414 sends a signal including information identifying thetransmitting monitor 412. The monitors 412 are positioned inside theroom adjacent to the doorway so that the signal is primarily within theroom and is strongest near the doorway 414.

As is discussed in more detail below, each monitor 412 is configured andplaced to preferentially interact with badges near the doorway withinthe room where the monitor 412 is mounted. As part of thisconfiguration, the transmission power levels of the transceiver 464 canbe controlled by the PLC chip 452 of the monitor 412. For example, ithas been found that monitors 412 mounted about 3-5 feet above the groundwith transceivers 464 transmitting at a power level of less than about 1milliwatts produce a signal of sufficient strength to trigger most orall badges 410 within about 3 feet of the doorway where the monitor 412is mounted while having sufficient signal loss to have low or no signaltransmission outside the room where the monitor is mounted and to havesufficient signal loss that relative signal strength can be used as anindicator of when a badge 410 is passing though the doorway beingmonitored. In some instances, the monitors can be mounted above thedoorway.

In some embodiments, the signal strength can be increased or decreasedin order to account for factors such as, for example, larger room orboundary dimensions. For example, the PLC chip can be programmed toactuate the transceiver 464 to transmit with a signal strength ofbetween about 0.25 and 5 milliwatts (e.g., about 0.5 milliwatts, about0.75 milliwatts, about 1.5 milliwatts, about 2.5 milliwatts).

In the illustrated embodiment, the transceiver 464 transmits on awavelength of about 2.4 GHz.

As shown in FIG. 17A, an exemplary badge 410 can include a greenindicator 418, a red indicator 420, an alcohol sensor grid 422, and amanual triggering button 424 on its outer casing 426. As shown in FIGS.17B and 17C, the badge 410 can include a badge board 428 powered by abattery 430 (e.g., a 3V lithium battery), both held within the outercasing 426. The badge board 428 includes a programmable logic controller(PLC) chip 432 coupled to a green LED 434, a red LED 436, a speaker 438,an alcohol sensor 440, and a transponder 444 which function insubstantially similar fashion to the corresponding elements of thepreviously described badge 200. The badge 410 also includes a manualtriggering switch 442, a real-time clock 446, and an accelerometer 448coupled to the PLC chip 432. The manual triggering switch 442 is used tomanually trigger a test cycle is as described in more detail below. Thereal-time clock 446 is used to establish the time at which various logevents such as, for example, test cycles occur.

The PLC chip 432 is configured to implement a state-control logic toencourage users to follow proper sanitation protocols. For example, thestate-control logic can be configured to activate a hand sanitationcheck both on entry to and exit from a monitored room. An exemplarystate-control logic is described in more detail below.

The badge can have a sanitized state indicated by activation of thegreen LED 434 and an un-sanitized state indicated by activation of thered LED 436. When the badge is initially activated, the PLC chip 432sets the badge 410 in its un-sanitized state. When the badge 410 is inan un-sanitized state, the PLC chip 432 activates the red LED 436 andshuts down other components including, for example, the alcohol sensor440. Pressing the manual triggering button 442 can trigger a cleanlinesstest cycle. After a successful cleanliness check is performed, the PLCchip 432 sets the badge 410 in its sanitized state. When the badge 410is in its sanitized state, badge components including the alcohol sensor440 and the red LED 436 are turned off, the PLC chip 432 is in alistening mode, and the green LED 434 is turned on.

In the embodiment described above, the PLC chip 432 uses the transponder444 to broadcast its badge identification signal upon receipt of alocation signal from a monitor 412. In some embodiments, badges 410 areconfigured to continually broadcast their badge identification signalsor are configured to broadcast their badge identification signals atpreset intervals as well as upon receipt of the location signal from amonitor 412.

The battery 430 powering the badge 410 can be a disposable battery or arechargeable battery. In the illustrated embodiment, the battery 430 isdisposable battery. In some embodiments, the badge 410 can be stored ina charger when not in use to recharge the battery 430. In someembodiments, the badge 410 includes photovoltaic cells instead of or inaddition to the battery 430. For example, the badge 410 can beconfigured to operate using photovoltaic cells for power when sufficientambient light is available and the battery 430 as a supplementary orreplacement power source when the photovoltaic cells do not provideenough power.

The accelerometer 448 (e.g., a three-axis accelerometer such theMMA7260Q Three Axis Low-g Micromachined Accelerometer commerciallyavailable from Freescale Semiconductor of Chandler, Ariz.) sends asignal to the PLC chip 432 indicating whether the badge 410 is inmotion. The PLC chip 432 can be programmed to shut down the badgecomponents after a set period of time (e.g., 10 minutes, 20 minutes, 30minutes, or 60 minutes,) passes without the accelerometer 448 indicatingthat the badge 410 is in motion. For example, if the badge 410 is storedin a physician's desk when she leaves the hospital, the badge 410 willshut down to conserve the battery 430 after the set period of timepasses.

As shown in FIG. 18, the components of the badge 410 are substantiallysimilar to the components of the badge illustrated in FIG. 14 with theaccelerometer 448 added. The accelerometer 448 is connected to the PLCchip 432.

FIG. 19 illustrates an exemplary state-control logic that can beimplemented on PLC chips 432 of the badges 410 used as part of thesystem 400 illustrated in FIGS. 15A and 15B. FIG. 15B shows a system 400with monitors 412 a, 412 b, 412 b installed in patient rooms 474 a, 474b, 474 c near doorways 414 a, 414 b, 414 c from hallway 475.

The badges 410 can be activated, for example, when a badge 410 isremoved from a charger where it is being stored, when an accelerometer448 on a “hibernating” badge 410 indicates that the badge once againbeing moved, or when a user manually activates a badge 410. When thebadge 410 in the illustrated embodiment is initially activated, the PLCchip 432 sets the badge 410 in an un-sanitized state and a user pressesthe manual triggering button 442 to start a cleanliness test cycle. Insome embodiments, the PLC chip 432 automatically starts a testing cyclewhen a badge 410 is activated.

Upon starting the cleanliness check cycle, the PLC chip 432 activatesthe alcohol sensor 440 and, while the alcohol sensor 440 is warming up,activates visual or audible indicators to indicate that the badge 410 isin a pre-test state. For example, the PLC chip 432 can turn the greenand red LEDs 434, 436 on and off in an alternating sequence to indicatethe badge is in a pre-test state. After the alcohol sensor 440 is readyto perform a test, the PLC chip 432 activates visual or audibleindicators (e.g., turns the red LED 436 steadily on in an alternatingsequence) to indicate that the user can perform a cleanliness check. Insome embodiments, the PLC chip 432 sets the badge 410 in testing modeafter a set period of time. In some embodiments, the PLC chip 432monitors the temperature and/or other parameters of the alcohol sensor440 to determine when the alcohol sensor 440 is ready to perform a test.If a successful cleanliness check is performed, the PLC chip 432 setsthe badge 410 in a sanitized state. If a set period of time (e.g., 30seconds) passes without a successful cleanliness check being performed,the PLC chip 432 sets the badge 410 in an un-sanitized state. To clearthe indication that it is in an “un-sanitized” state, the user can pressthe manual trigger button which signals the PLC chip 432 to beginanother cleanliness check cycle.

As described with reference to the other badge embodiments, during acleanliness check cycle, a user places a portion of their hand againstthe alcohol sensor grid 422 of their badge 410 and the PLC chip 432assesses whether there is sufficient alcohol on the user's hands toindicate that they are clean. After a successful cleanliness check isperformed, the PLC chip 432 sets the badge 410 in its sanitized state.When the badge 410 is in its sanitized state, badge components includingthe alcohol sensor 440 and the red LED 436 are turned off, the PLC chip432 is in a listening mode, and the green LED 434 is turned on.

In the exemplary system 400, the badges 410 are configured to prompt auser to wash his or her hands each time they enter or exit a patient'sroom. For example, after activating her badge 410 a and performing asuccessful cleanliness check to set her badge 410 a in its sanitizedstate, a doctor starts her rounds which include visiting patients inthree rooms 474 a, 474 b, 474 c shown on FIG. 15B.

As the doctor passes through the doorway 414 a into a first room 474 a,the motion detector 416 signals the PLC chip 452 in the monitor 412 athat there has been motion in the doorway 414 a. In response, the PLCchip 452 operates the transceiver 464 to send a wireless signalincluding identification information (e.g., a serial number) of themonitor 412 a. In this embodiment, each monitor 412 includes a detector416 (e.g., an infrared motion detector) which indicates when someonepasses through doorway 414. The monitor 412 can be configured totransmit a signal only when the detector 416 indicates that someone ispassing through the doorway 414. In some embodiments, the monitors 412can be configured to transmit signals continuously.

In operation, the state of badges 410 are controlled by the statecontrol logic 500 illustrated in FIG. 19. The state control logic 500 isdesigned to trigger a cleanliness test cycle when a badge 410 crosses amonitored threshold 414 (e.g., entering or exiting a patient's room)which is generally indicated by receipt of a signal from a monitor 412.The state control is also designed to assess whether a signal receivedfrom a monitor 412 was transmitted in response to someone else crossingthe monitored threshold 414. It may be undesirable for the badges 410 ofpeople already in a space who have cleaned their hands to be triggeredby the entry of another person into the space.

In its sanitized state, the badge 410 displays a green light and listensfor signals from monitors 412 (step 510). Until a signal is receivedfrom a monitor 412, the badge remains in listening mode. In listeningmode, a cleanliness test cycle can be triggered by passage of timeand/or by an override signal from a central controller as described withrespect to the other embodiments. When the badge 410 receives the signaltransmitted by a monitor 412 (step 512), the PLC chip 432 on the badge410 checks whether this is a new monitor signal (step 514). For example,the PLC chip 432 can compare the received signal with a previouslystored signal (e.g., the most recently stored signal in a time-orderedqueue 409 of monitor signals stored in onboard memory of the badge 410).If the previously stored location signal is different than the currentlyreceived location signal, the badge 410 activates a cleanliness checkcycle (step 520) based on the assumption that the person wearing thebadge 410 has entered a new monitored room. The PLC chip 432 also storesinformation about the new signal (e.g., the identification of thetransmitting monitor and the signal strength) in the time-ordered queueof monitor signals stored in onboard memory of the badge 410.

The movement of people or objects other than the person wearing a badge410 through a doorway can cause a monitor at that doorway to transmit amonitor signal. In some embodiments, the badge 410 monitors the presenceof other badges in a room to avoid being set to an un-sanitized statewhen this occurs. For example, if the monitor signal has the same sourceas a previously received signal (e.g., the same source as in the mostrecently stored signal information 411 in the time-ordered queue ofmonitor signals stored in onboard memory of the badge 410), this mayimply that the person wearing the badge 410 may be remaining in a roomwhose monitor has transmitted a monitor signal in response to beingtriggered. In some embodiments, if the monitor signal has the samesource as a previously received signal, the PLC chip 432 returns thebadge to listening mode. In the illustrated embodiment, the PLC chip 432is configured to receive identification signals transmitted by otherbadges 410 to track which badges are within a specified distance (e.g.,within the same room) (step 516). In this embodiment, the PLC chip 432can be configured to activate the cleanliness check cycle (step 520) ifthere has not been a change in the badges present when the monitorsignal is the same as for the previously stored signal. Other approachescan also be used to identify and track the population of badges in aroom and use that information is a basis for avoiding the triggering ofthe badges of people already in a room due to the passage of otherpeople through the entrance of the room.

In some embodiments, if there has been a change in the badges present,indicating that another person has entered or left a space beingmonitored, the PLC chip 432 returns the badge to listening mode. In theillustrated embodiment, the PLC chip 432 is configured to monitor thestrength of signals received. In this embodiment, the PLC chip 432returns the badge to listening mode if the received signal strength of amonitor signal that is the same as the previously stored monitor signalis less than a certain percentage (e.g., 90%, 80%, or 70%) of themaximum signal strength recorded for a signal from that monitor (step518). Otherwise, the PLC chip 432 can the person wearing the badge 410is passing through a doorway and therefore activate the cleanlinesscheck cycle (step 520). This approach assumes that the maximum signalstrength for a monitor is recorded as a health care worker wearing abadge walks through the adjacent doorway.

If the cleanliness check cycle is activated (step 520), the user canoperate the badge as described above to check that sufficient alcoholvapor is present to indicate that the user's hands are sanitized. If thetest is successful (step 522), the PLC chip 432 can reset the badge toits sanitized state (step 528) and return to the listening mode (step510).

As discussed with respect to other embodiments, the badges 410 can storecleanliness test results in onboard memory. The test results andassociated data can be periodically downloaded to a base station 523.FIG. 20 illustrates the application architecture for an embodiment ofthe base station which receives data from the badges 410, stores thedata in a database, and provides access to the data (e.g., web-basedaccess). FIG. 21 illustrates a portion of a graphical user interfacethat can be used to access the data.

In some implementations, monitors 412 can be configured to continuouslysend badge-switching signals across a doorway or threshold 414. Forexample, the monitors 412 can include shielding which localizes thebadge switching signal being transmitted to the doorway 414 or otherthreshold being monitored. The badges 410 can be programmed to switch toa non-sanitized state whenever a badge-switching signal is receivedbased on the assumption that whenever a badge-switching signal isreceived the wearer is entering or exiting a room by crossing amonitored threshold.

This approach can result in “false positives” in which the systemmistakenly triggers a cleanliness check cycle for person who merelypasses by (rather than crosses) a threshold.

In some implementations, the monitors 412 can continuously sendbadge-switching signals throughout the room in which the monitors 412are installed. The associated badges 410 switch to a non-sanitized stateupon first receiving a badge-switching signal from a specific monitor412. After the person wearing the badge 410 has cleared thenon-sanitized state by running a successful test cycle, the badge 410will ignore the badge-switching signal transmitted by the specificmonitor which triggered the test cycle as long as the badge 410 remainsin communication with that specific monitor. The badge interprets a lossof communication with that specific monitor as indicating that thewearer has exited the monitored space and switches to a non-sanitizedstate upon loss of communication. This approach does not require themonitor to include a detector but can sometimes result in the badge 410unnecessarily switching to a non-sanitized state. For example, if atechnician wearing a badge 410 moves behind a badge that blocks thesignal from the monitor 412, the badge could be switched to anon-sanitized state. The badges 410 can be configured with a time-delaybefore the signal loss switches the badge state as a method of reducingsuch unnecessary switching.

As illustrated in FIGS. 22A-22D, some embodiments of a system 600configured to prompt individuals 601 (e.g., health-care workers, onlyone shown) to sanitize their hands 603 on entering or exiting a specificspace (e.g., a patient's room) include badges 610 (only one shown inFIG. 22A), a monitor or monitors 612 a, 612 b that provide dual signalsat a threshold of the space, such as a doorway 605, and a base station614. In these embodiments, the wearable badges 610 can prompt a user toclean his or her hands, verify that his or her hands have been cleaned(e.g., sense the presence of alcohol hand sanitizer), and record theactivities of the wearer. The monitors 612 a, 612 b can be mounted abovean entrance 613 (an example of a threshold) to a space (e.g., above adoorway leading into a patient's room) emitting at least two signalbeams 615, 617 downward as a way to trigger a hand-cleaning process. Asexplained in more detail below, the badges 610 are configured torecognize that they have crossed a boundary based on rapid transitionsin the receipt at the badge of different signal beams. This dual signalbeam approach can reduce the likelihood of that badges 610 willunnecessarily switch to a non-sanitized state.

The base station 614 (see FIG. 22B) can collect data from multiplebadges and provide an overview of hand-cleaning events.

The monitors 612 a, 612 b can be mounted above the doorway of a roomeach to emit a signal-carrying beam 615, 617 (e.g., infrared light) in adownward direction 619. In some embodiments, the monitors 612 a, 612 bcan be adhesively attached to a door frame or wall. In some embodiments,the monitors can be mechanically attached to the door frame or wall.

The monitors can be mounted with first monitors 612 a inside the doorwayand second monitors 612 b outside the doorway. For example, in someimplementations, the monitors 612 a, 612 b can include infrared lightemitting diodes (LEDs) which continuously emit infrared light downwardstowards a floor 616 in the form of a conical infrared light beam 623 anangle of dispersion a (FIG. 22D) substantially perpendicular to theplane 625 of the doorway of about 60 degrees (e.g., between about 50 and70 degrees) and at an angle of dispersion (FIG. 22A) substantiallyparallel to the plane of the doorway of about 60 degrees (e.g., betweenabout 50 and 70 degrees). As can be seen in FIGS. 22C and 22D, thisconfiguration can provide a signal field 627 that is localized in thevicinity of the threshold 629 being monitored. This configuration canprovide lateral overlap between the signal beams from adjacent insidemonitors in order to provide uninterrupted coverage and between thesignals from adjacent outer monitors with limited or no overlap betweenthe signal beams of inside monitors and the signal beams of outsidemonitors.

In a test of the illustrated embodiment, the monitors used were mountedas illustrated in FIG. 22E. Two inside monitors 612 a were mounted about24 inches apart (e.g., about 12 inches from the doorway centerline) onthe inner upper frames of 30 inch doorways and two outside monitors 612b were mounted at corresponding locations on the outer upper frames ofthe doorways. The alpha and beta angles of dispersion were about 60degrees and 60 degrees respectively. This configuration provided lateraloverlap between the signals from adjacent inside monitors and betweenthe signals from adjacent outer monitors with limited or no overlapbetween the signals of inside monitors and the signals of outsidemonitors.

FIGS. 28A-28B illustrate an approach to mounting the monitors 612 a. Inthis approach, the pairs of monitors 612 a are mounted above or slightlyoutside the side edges of the door frame. Each of the monitors 612 a caninclude an infrared light emitting diode 655 disposed in a plasticsleeve 657 (e.g., a cylindrical plastic sleeve) to confine and directthe infrared light. Each of the monitors 612 a can also include a cover659 (e.g., a plastic cover opaque to visible light and translucent toinfrared light) that is on the side of the monitor facing the room orhallway. This implementation of monitors 612 a can improve the focus anddirectivity of the infrared light beam, inside and outside of doorways.

FIGS. 29A-29C illustrate a monitor 612 a implemented as a “lightcurtain.” The monitor 612 a can include multiple infrared light emittingdiodes 655 arranged in a light strip within a cover 659 (e.g., a plasticcover opaque to visible light and translucent to infrared light). Aplastic sleeve 657 (e.g., a rectangular shroud on the side of themonitor facing the room or hallway) extends over the multiple infraredlight emitting diodes 655 to confine the infrared light emitted by themonitor to the vicinity of the doorway, that is, to confine the infraredlight to a space that is typically no more than 36 inches into the roomor hallway relative to the door. The sleeve can be attached to amechanism (e.g., a lever, an adjustable screw mount) operable to controlthe position of the plastic sleeve relative to the light emitting diodes655 and, thus, the configuration of the infrared beam emitted by themonitor 612 a.

Monitors are available that have a variety of emitter coverage patterns.The system 600 can be designed using monitors that have differentemitter coverage patterns and/or different configurations of monitors.For example, larger boundaries (e.g., the threshold between the centralaisle and bed spaces of an open bay ward or large double doorways) canbe covered by more monitors and/or by monitors with wider emittercoverage patterns arranged to provide the rapid transition between innerand outer signals used to identify the boundary location. For example,in some embodiments, a badge can identify a boundary if the transitionbetween signals occurs in less than 2 seconds (e.g., less than 1 secondor less than 0.5 seconds). In some embodiments, a single monitor can beconfigured to provide both inner and outer signals with limited or nooverlap between the inner signals and the outer signals.

The terms “inside,” “inner,” “outside,” and “outer” are used for ease ofdescribing the locations relative to the hallway-room building planshown in FIG. 22B. Such monitors could be used to identify boundarylocations in other settings including, for example, an outdoor boundaryline where none of the monitors used are inside a building or a shapedefined by the boundary.

The first monitors 612 a mounted inside the doorway and second monitors612 b mounted outside the doorway emit different signals (e.g., theinfrared beams of different monitors can be modulated to carry differentidentification signals). As is discussed in more detail below, thebadges 610 can identify when the user crosses the threshold beingmonitored and the user's direction of travel based on the differentsignals emitted by the first monitors 612A and the second monitors 612B.In some embodiments, each monitor 612 emits a unique signal (e.g., aserial or identification number). In these embodiments, the locations ofindividual monitors 612 can be pre-stored in a database on the badges610 and/or at a central monitoring station. In some embodiments, thefirst monitors 612 a emit a first common signal and the second monitors612B emit a second common signal, for example, a signal that indicatesthat a given monitor is either an inside monitor or an outside monitor.

In a test of the illustrated embodiment, the monitors 612 wereconfigured to continuously emit a beam of infrared radiation modulatedto carry identification signals that were received by any badge withinrange (e.g., passing through a monitored doorway). As illustrated inFIG. 23, each of the monitors 612 included a PLC chip as amicrocontroller unit (MCU) 616 and a USB connector 618 to provideoperator access to the MCU (e.g., to set the signal being emitted by themonitor 612). A power control 620 connects the MCU to a power input 622.In the test, the monitors 612 were powered by wall plugs. In someembodiments, the monitors 612 can be powered by other means including,for example, photovoltaic cells and/or batteries. The MCU 616 controlledthe infrared signal emitted by infrared a light emitting diode 624through an infrared transmit driver 626. Connections 626 available forup to three other light emitting diodes were not used.

In this embodiment, the monitors 612 did not utilize any sensors orradiofrequency communications, but acted simply as a trigger to causebadges to record events corresponding to entering or exiting a room. Themonitors 612 used in the test included radiofrequency transceivers 628with antennas 630 to provide additional communication links forradiofrequency communication as needed. Such radiofrequency transceiverscan provide high rate data transmission.

As illustrated in FIGS. 24 and 25, the badges 610 used in the test hadmultiple functions that were controlled by a microcontroller unit 640(e.g., a PLC chip and associated software). The badges 610 weregenerally similar to the badges 410 but did not include a manualtriggering button. A wakeup logic application 642 monitored signals froma photodiode 644 activated by infrared light. The badges 610 wereconfigured to continuously monitor their environments using thephotodiode, and were activated by the infrared light of the monitors612. Once activated, the MCU 640 received the infrared-carried signalsfrom the monitor 612 using an infrared receiver 646 and associatedsignal processing application 648 to determine and store the monitoridentification and then initiated a cleanliness test cycle. In the test,the location of the monitor 612 was correlated with its location in adatabase stored on a central server. In some embodiments, the locationdatabase can be stored in onboard memory of the badge 610 rather than orin addition to on the central server.

When the cleanliness test cycle was initiated 7, the badge 610 promptedthe user to clean his/her hands, warmed up an onboard alcohol sensor648, then prompted the user again to place his/her hands near thealcohol sensor 648 using light emitting diodes and/or a speaker 650. Atthis point, the sensor 648 tested for the presence of alcohol bymeasuring the increase or decrease in voltage level from a metal oxidealcohol sensor.

The badge 610 communicated the success/failure of the alcohol test tothe user via light emitting diodes 650 and sounds, and stored a recordof the time, location, and status of the alcohol test in memory capableof holding data about hundreds of testing events. The data wasdownloaded into the base station reader 614 periodically. The badgesused in the test downloaded data using a USB interface port 654 (andassociated cable) connected to the MCU 640 through a power controlmodule 656. A battery 658 (e.g., a rechargeable battery) was alsoconnected to the power control module 656.

Although the badges 610 used in the test did not include radio frequencytransceivers, some badges include radiofrequency transceivers 628 withantennas 630 to provide an additional communication link in case of anypotential need for radiofrequency communication including, for example,when downloading data from the badges. Such radiofrequency transceiverscan provide high rate data transmission. In some embodiments, the badgesare configured to use an automated wireless download rather than the USBport/cable. In automated wireless download embodiments, when a healthcare worker passes, for example, a base station 614, his/her badge 610is triggered to transmit stored test data to the base station 614.

Similarly, although the badges 610 used in the test did not includeaccelerometers, some badges include accelerometers 652 which can providethe MCU with input for battery saving shutdown scheme.

FIGS. 25A-25K provide a wiring schematic for embodiments of the badges610, monitors 612, and base stations 614. FIGS. 31A-31J also providewiring schematics for embodiments of a badge 610 and a base station 614.

The base station 614 can be a PC-based application that includes a USBinterface operable to connect to USB ports on the badges 610. The basestation reader software organizes the badge data 6101 into a commadelimited text file (.csv file) 6102 which compiles the time 6103,location 6104, badge identifier 6105, and success/failure of each handcleaning event for multiple badges. The .csv file can then be importedto Excel for sorting/viewing of data. In some embodiments, the badges610 include an RF transmitter and the base station 614 includes an RFreceiver which can be used to transfer data from the badges 610 to thebase station 614.

FIGS. 26, 27A-27D, and 30 illustrate the sequence of events that occurswhen the un-sanitized mode of a badge 610 is triggered by passagethrough a doorway or other monitored boundary. Upon powering up, thebadge 610 enables its IR detector and the badge microprocessor monitorsthe badge IR detector, to detect patterns of IR light (sequences ofoff/on light bursts) which indicate the presence of a monitor. When amonitor is detected, the badge 610 registers the Orb #, System ID #, andthe “indoor” or “outdoor” status of the monitor. When the badge detectsanother monitor and registers the same Orb#/System ID # with theopposite “indoor/outdoor” designation, the badge 610 recognizes atransition event.

A doctor standing in the hall passes through the doorway 475 into room474A passing under monitor(s) 612 aa and 612 ab on the outside 477 ofthe door frame 479 and then under monitor(s) 612 bb and 612 bc on theinside 481 of the door frame 479. The doctor's badge 610 is activatedfrom its listening mode when photodiode 644 (see FIG. 24) receivesinfrared light from monitor(s) 612 a. As the doctor passes through thedoorway, the infrared receiver 646 of the badge 610 receives anidentification signal from monitor(s) 612 a and then from monitor(s) 612b. As monitor 612 a and monitor 612 b have the same Orb#/System ID #with the opposite indoor/outdoor designations, the badge 610 recognizesa transition event.

The receipt of sequential infrared signals triggers a hand cleanlinesstest cycle 654. The badge 610 starts the process of warming up thealcohol sensor 660 and indicates that a test is required (e.g., byalternately flashing the red and green light emitting diodes) 662 and/orby emitting an audible signal (e.g., one or more audible beeps). Themicroprocessor monitors the voltage output of the tin-oxide sensor toestablish a baseline of output for “clean” air, then emits a series ofbeeps to signal its readiness for an alcohol test to the user. The “testrequired” signaling continues 664 for about 8 seconds (e.g., between5-10 seconds) which allows the doctor to wash her hands with, forexample, an alcohol based cleaner. The badge 610 then signals 666 (e.g.,by a soft buzzing sound and/or a blinking red light emitting diode) thatthe doctor should apply one of her fingers to or near the alcohol sensorand the warm up cycle ends 668. The MCU then executes a cleanlinesscheck as described above with respect to other embodiments. If there issufficient alcohol vapor present for a successful test, the badgesignals a successful test 672 by, for example, turning off the red lightemitting diode, turning on the green light emitting diode, and making apleasing sound. The badge then resets to listening mode. If there is notsufficient alcohol vapor present for a successful test, the badgesignals an unsuccessful test 672 by, for example, flashing the red lightemitting diode and making an unpleasant sound. The badge can then returnto the start of the warm up cycle 660 for a retest sequence.

Multiple (e.g., up to 3, up to 4, or up to 5) retest sequences arerepeated until the badge discontinues testing and the red light emittingdiode on the badge is turned on, a failed test is recorded, and thebadge returns to listening mode. If, during the initial check 658, theMCU found that a complete failed or bad test had occurred since thebadge was activated by passage through the doorway, the red lightemitting diode on the badge is turned on, a failed test is recorded, andthe badge returns to listening mode without activating the alert signalsdiscussed above (e.g., flashing lights, sounds, vibration). This bypassallows the badge to be silenced without operator intervention or asuccessful hand washing check under circumstances when other activitiesare more important than hand washing. For example, if the doctor hadentered room 474A during rounds to make a routine check on a patient,her badge would prompt her to wash hands using the signals describedabove. After she washed her hands and completed a successful cleanlinesscheck, her badge 610 would be set to its sanitized state and woulddisplay, for example, a steady green light. However, if the doctor hadentered room 474A because the patient had suffered a heart attack,multiple health care workers would likely be entering room 474A in closesuccession and all of their badges would be triggered to signal the needfor hand washing. However, under these circumstances, the need forurgent medical intervention might preempt hand washing. After threetests which would be unsuccessful because the health care workers wouldnot be applying their fingers to or near their badges 610, the badgeswould stop the possibly distracting signaling.

In either case, when the doctor left room 474A and entered room 474B,her badge would be triggered when she entered the hallway andretriggered when she entered room 474B. After she washed her hands andcompleted a successful cleanliness check, her badge 610 would be set toits sanitized state and would display, for example, a steady greenlight. If the doctor entered room 474B without washing her hands andcompleting a successful cleanliness check in the hall, her badge wouldrecord passing through the hallway as a failed cleanliness check.

After the doctor left room 474B and went to a central desk station, herbadge would be triggered as she passed through the doorway. Her badgewould prompt her to wash hands using the signals described above and,after she washed her hands and completed a successful cleanliness check,her badge 610 would be set to its sanitized state and would display, forexample, a steady green light.

Base station 614 could be located at the central desk station. Healthcare workers such as the doctor could periodically (e.g., at the end ofeach shift) download data from their badges 610 to the base station (seeFIG. 30).

In some embodiments, the badges 610 include an onboard emitter (e.g., RFtransmitter) and the base station 614 includes an RF receiver which canbe used to transfer data from the badges 610 to the base station 614.For example, the base station 614 can transmit a signal (e.g., an RFbeacon signal (802.15.4) every 750 milliseconds or continuously transmitan IR signal) identifying the base station and system ID# (step 710).

The onboard emitters on the badges 610 can be switched from a defaultinactive state to an active state to transmit information upon receiptof the signal identifying the base station and system ID# (or otherexternal receiving equipment). Badges 610 whose onboard emitters areactivated by the base station 614 can respond, for example, bytransmitting an acknowledgement signal using 802.15.4 wireless signalprotocols. When the base station 614 receives an acknowledgement signalfrom a badge 610 (step 712), the base station 614 can respond to thebadge 610 that the base station 614 is ready to receive data. The badge610 can authenticate that the base station 614 has the appropriateSystem ID, then transmit its records.

The base station 614 receives a message indicating the number of recordsto be transmitted by the badge 610 (step 714), receives data recordsfrom the badge 610, and translates the records received from the badge610 into a format which can be stored (step 718), for example, on alocal PC in a text-delimited data file. The base station compares thenumber of records received to the expected number of records (step 720).If the number of records match, the base station 614 can transmit anacknowledgement to the badge 610 to indicate accurate receipt of dataand can return to its beacon mode (step 722). In some embodiments,separate software on the PC is used to pass the data file throughnetwork connections to a storage database, either online or within thehospital server network.

The badge 610 can disable its onboard emitter (e.g., RF transmitter),erase its memory, and return to the passive monitoring state afterreceiving confirmation from the base station 614 that the downloadednumber of records have been received.

This approach can limit emissions (e.g., radio frequency emissions) fromthe badges 610 except when devices are triggered to download informationto the external receiving equipment. For example, it can be desirable tolimit emissions in the patient care portion of a hospital room.

After downloading her badge 610 (e.g., by USB connection to the basestation 614 or RF transmission of data while passing the base station614), the doctor walks down the hall. Her badge receives signals 612 a,612 a′, 612 a″ from monitors on the outside of the doorways of rooms474A, 474B, 474C. Because the received signals 612 a, 612 a′, 612 a″ areall “outside” signals, the badge 610 determines that it has not crosseda monitored boundary and does not activate a cleanliness check cycle.

Similar approaches can be used to promote good sanitary practices inother spaces (e.g., open bay wards and nurseries) in which it isdesirable that individuals sanitize their hands both on entering and/orexiting the specific space. More generally, similar systems can be usedto prompt good hygiene in a healthcare environment, and may also be usedin restaurants, cruise ships, and other environments where good hygieneis important.

A wide variety of other implementations are within the scope of thefollowing claims.

For example, the hand washing routines described above can beimplemented based on badges identifying hand cleanliness by the presenceof alcohol vapors on a user's hands. However, similar logic could beused to trigger hand wash signals for badges which are reset to asanitized state by other means including, for example, registering theoperation of equipment such as a faucet and soap dispenser or bymonitoring the time spent in front of a soap-and-water sink with asuccessful hand-cleaning event determined after a prescribed period oftime is spent at the sink.

In another example, some badge embodiments include other battery lifeextension features. For example, an IR detector on the badge can bedisabled during a charging cycle. Onboard emitters (e.g., an RFtransceiver) can be disabled until a sensor on the badge detects a “BaseStation Orb”. The cleanliness sensor (e.g., alcohol sensor) can bedisabled until the badge detects a “Room Transition”, then the tin-oxidesensor is warmed up with electrical current. The light emitting diodescan be used in “blinking” mode instead of constantly on. When triggered,cleanliness tests are repeated a limited number of times (e.g., fourtimes) in response to failures before being discontinued to save power.

The invention claimed is:
 1. A system to encourage compliance with handwashing procedures, the system comprising: a first beacon, associatedwith a boundary, to transmit a first identification signal; and a secondbeacon, associated with the boundary, to transmit a secondidentification signal; wherein a transition, in a vicinity of theboundary, between the first identification signal and the secondidentification signal indicates the boundary, wherein the first beaconemits a first beam that carries the first identification signal and hasa transverse cross-section having a maximum length along a first axis,wherein the first beacon is oriented with the first axis of the firstbeam substantially parallel to the boundary.
 2. The system of claim 1,further comprising a wearable device comprising: a receiver to receivethe first identification signal and the second identification signal; anindicator to indicate a cleanliness state of a user's hands; and acontrol unit to control the indicator of hand cleanliness based at leastin part on information from the receiver.
 3. The system of claim 2,wherein the control unit of the wearable device comprises logic toevaluate whether the wearable device is crossing the boundary based onreceipt of the first identification signal and the second identificationsignal by the receiver.
 4. The system of claim 1, wherein the firstbeacon and the second beacon each comprise an infrared emitter.
 5. Thesystem of claim 1, wherein the first and second beacons have elements toattach the first and second beacons to a wall, and the boundary isimplied by the wall.
 6. The system of claim 1, wherein the boundary isdefined by a doorway though a wall and the first beacon is attached onone side of the wall and the second beacon is attached on an oppositeside of the wall.
 7. The system of claim 1, wherein the firstidentification signal carries information indicative of which one of twosides of the boundary the first beacon is on.
 8. The system of claim 1,wherein the transverse cross-section has a length along a second axisperpendicular to the first axis, wherein a ratio of the length along thefirst axis to the length along the second axis is at least 3:1.
 9. Thesystem of claim 8, wherein the first beacon projects an infrared beamdownwards towards a floor and an average length of the first axis of thefirst infrared beam is between about 20 and 28 inches.
 10. The system ofclaim 9, wherein an average length of the second axis of the firstinfrared beam is between about 6 and 10 inches.
 11. The system of claim1, comprising emitters each to transmit an identity signal that includesinformation identifying the transmitting emitter.
 12. A system toencourage compliance with hand washing procedures, the systemcomprising: an infrared emitter that projects a first infrared beam witha transverse cross-section having a first axis and a second axis shorterthan the first axis, the transverse cross-section having a maximumlength along the first axis, the infrared emitter modulating the firstinfrared beam to transmit a first identification signal; wherein theinfrared emitter projecting the first infrared beam is placed with thefirst axis of the transverse cross-section of the first infrared beamsubstantially parallel to a boundary.
 13. The system of claim 12,further comprising an infrared emitter that projects a second infraredbeam with a transverse cross-section having a first axis and a secondaxis shorter than the first axis, the transverse cross-section having amaximum length along the first axis, the infrared emitter modulating thesecond infrared beam to transmit a second identification signal; whereinthe infrared emitter projecting the second infrared beam is placed withthe first axis of the transverse cross-section of the second infraredbeam substantially parallel to the boundary on an opposite side of theboundary from the first infrared beam.
 14. The system of claim 12,further comprising a wearable device comprising: an infrared receiver;an indicator operable to indicate a cleanliness state of a user's hands;and a control unit operable to control the indicator of hand cleanlinessbased at least on part based input from the infrared receiver.
 15. Thesystem of claim 14, wherein the controller of the wearable devicecomprises logic operable, on receiving the infrared receiver, toevaluate whether wearable device is crossing the boundary.
 16. A systemto encourage compliance with hand washing procedures, the systemcomprising: an emitter that projects a first beam with a transversecross-section having a first axis and a second axis shorter than thefirst axis, the transverse cross-section having a maximum length alongthe first axis, the infrared emitter modulating the first beam totransmit a first identification signal; wherein the emitter projectingthe first beam is placed with the first axis of the transversecross-section of the first beam substantially parallel to a boundary.17. The system of claim 16, wherein the emitter is a radiofrequencytransmitter.
 18. The system of claim 17, wherein the emitter comprisesshielding configured to limit lateral transmission of a radiofrequencysignal emitted by the radiofrequency transmitter.
 19. The system ofclaim 16 wherein the emitter comprises an infrared emitter.
 20. Thesystem of claim 16 wherein the emitter is configured to project thefirst beam in response to a signal from a motion detector.